Present technology digital devices, having digital processors, e.g., microcontrollers, microprocessors, digital signal processors (DSP), etc., and/or peripheral modules, e.g., memories, analog-to-digital converters, digital-to-analog converters, industry standard interfaces such as Ethernet, Firewire, Fibre Channel, etc., when configured to use an external clock, the digital device designs assumed that the external clock would run at a clock frequency commensurate with the fastest possible operating speed of the digital devices. Biasing of circuits in the digital devices that were dependent upon the frequency of the device operation had to assume a worst case design scenario, and thus were set to the highest power mode so as to be able to accommodate the fastest possible device operating frequency. This was wasteful for power utilization and power dissipation in the digital devices.